Valve for rock drills



Aug. 27, 1929. c L s I I 1,726,334

VALVE FOR ROCK DRILLS Filed April 6, 1927 INVENTOR. Le z'aLIBa Zea. BY /'v 7 H15 ATTOR EY Patented Aug. 27, 1929.

UNITED STATES PATENT OFFICE.

LEwIs c. BAYLES, 0E EASTON, PENNSYLVANIA, ASSIGNOR To INGERSOLL-RAND COMPANY, 0E JERSEY crrY, NEW JERSEY, A CORPORATION on NEW JEnsEY.

VALVE FOR ROCK DRILLS.

Application filed April 6,

This invention relates to rock drills, but more particularly to a distributing valve for fluid actuated rock drills of the hammer type.

The objects of the invention are to obtain rapid distribution of the pressure fluid to the ends of the cylinder, to obtain a positive action of the valve, and to hold the inlet passages between the valve chamber and the cylinder to a minimum length.

Other objects will appear hereinafter, and to all of these ends the invention consists of the combination of elements and arrangement ofparts, having the general mode of operation substantially as hereinafter described and claimed and illustrated in the accompanying drawings, in which I Figure 1 is a longitudinal sectional elevation of a portion of a rock drill equipped with a valve constructed in accordance with the practice of the invention with the valve in one extreme position, and

Figure 2 is a viewsimilar to Figure 1 showing the valve in another extreme position.

Referring to the drawings, the invention is shown embodied in a rock drill having a cylinder A, a back head B and a front head C. A bushing D forms a closure for the front end of the cylinder A and is suitably bored to receive slidably an extension E of a hammer piston F reciprocable in the cylinder A.

The drill is provided with a valve chest Gshown in this instance disposed on the side of the cylinder A and extending longitudinally with respect thereto for illustrative purposes.

In the rearward and forward ends of the valve chest G are bushings H and J respectively, provided at their outer ends with flanges K. The flange K of the bushing J is adapted to abut the end of the valve chest G and also forms a seat for a nut L screwed on a bolt 0 for securing the bushing J in the valve chest. The flange K of the bushing H is seated in a recess P in the rearward end of the valve chest G and is of a length to substantially equal the depth of the recess P so that when the back head is pressed against the rearward end of the cylinder, said back head will also bear firmly against the bushing H to hold said bushing in the desired position.

The inner ends of the bushings H and J are suitably spaced with respect to each other to form a space Q, and this space Q, together with bores R and S of the bushings H and J 1927. Serial No. 181,453.

respectively, form a valve chamber for a distributing valve T.

The distributing valve T is of the hollow type having a bore U throughout its length and in this instance is provided with a central head V disposed in the space Q. The ends of the valve T are reduced in diameter and cooperate slidably with reduced portions WV of the bores R and S. By thus reducing the ends of the valve, shoulders X are formed on the valve intermediate its ends and the head V to serve as holding areas against which pressure fluid may act for holding the valve in thrown position.

In the construction shown, the bore U of the valve is in constant communication with the pressure fluid supply (not shown) through a passage Y communicating with the rearward end of the valve chamber. At the rearward end of the valve chamber is formed an inlet passage Z which leads to the rearward end of the cylinder and is controlled by the rearward end of the valve T. Likewise, at the front end of the valve chamber is formed an inlet passage Z) which leads to the front end of the cylinder A and is controlled by the front end of the valve T over which end the pressure fluid flows during its passage to the front end of the cylinder. Pressure fluid thus admitted to the cylinder is exhausted therefrom through a free exhaust port 0 preferably located intermediate the ends of the cylinder.

In order to actuate the valve T from one limiting position to another, a pair of kicker passages 03 and e are formed in the valve chest G for the admission of pressure fluid from the cylinder A into the valve chamber. For the best operation of the drill, the kicker passages d and e are crossed, that is, the passage d leads from a point rearwardly of the center of the cylinder to the forward end of the space Q, and the passage 6 from a point forwardly of the center of the cylinder A to the rearward end of the space Q. By this arrangement the passage (Z will convey pressure fluid to the front end of the space Q, to act against the actuating area f at the forward end of the valve head V and the passage 6 will convey pressure fluid to the rearward end of the space Q to act against the rearward actuating surface 9 of the valve head V.

In order to prevent trembling of the valve T after it has been actuated to one or the other of its limiting positions, the bushings it into the cylinder.

H and J are provided with leak ports h and 9' respectively to convey pressure fluid from the inlet passages Z and Z) to the bores R and S of the bushings to act against the shoulders X of the valve.

Means are provided for controlling the ex haust of air compressed by the piston F in the ends of the cylinder A. To this end the cylinder A is provided with a valve chamber 7; which communicates at its ends'with the corresponding ends of the cylinder A through small kicker ports 0 and p.

In the chamber A is disposed a compression relief valve q comprising a stem 1" and end heads 8 and t for controlling compression relief ports a and a; near the rearward and front ends respectively of the cylinder A. Preferably communication between the valve chamber 75 and the atmosphere is afforded by a plurality of small exhaust ports to for exhausting the pressure fluid from the valve chamber 70.

The operation of the device is as followsi With the valve T and the piston F in the positions illustrated in Figure 1., pressure fluid flowing through the passage Y will pass through the inlet passage Z into the rearward end of the cylinder to impel the piston forwardly. Simultaneously with the admission of pressure fluid to the rearward end of the cylinder, a portion thereof will pass into the rearward end of the valve chamber is and, acting against the head 8 of the valve 9, will hold the said valve 9 forwardly so that the head 8 of the valve Q will cover the relief port a, thus preventing leakage of live pressure fluid from the rearward end of the cylinder to the atmosphere. At the same time a portion of the pressure fluid will flow from the inlet passage Z through the leak port it into the bore R to act against the shoulder X for holding the valve in its forward position. The pressure fluid utilized for this purpose remains in the bore R until the rearward end of the cylinder is opened to atmosphere, whereupon it is exhausted through the port This occurs after the piston uncovers the exhaust port 0 and after the passage Z is closed to admission by the valves T but before the valve has reached its extreme seating position, thus allowing time for the fluid to escape without delaying admission to the other end of the cylinder at the port I). As the piston proceeds in a forwardly direction the kicker passage (Z will be uncovered thereby, thus admitting pressure fluid into the front end of the space Q, to act against the front actuating surface f and actuate the valve T rearwardly to the position illustrated in Figure 2. The pressure fluid thus utilized for actuating the valve will immediately be exhausted to the atmosphere through the exhaust port G. Upon the admission of pressure fluid into the front end of the cylinder through the inlet passage 5, a portion of pressure fluid will flow through the leak port j to act against the forward shoulder X and hold the valve in its rearwardmost position. It will be apparent that the valve will be thus held firmly in the manner described until the piston uncovers the kicker passage 6, whereupon pressure fluid will be admitted into the rearward end of the space Q to act against the actuating surface 9 of the valve head V to again move the valve t forwardly.

Shortly after the piston uncovers the kicker passage 6 said piston will also overrun the free exhaust port 0 and the pressure fluid in the front end of the cylinder will then pass through said free exhaust port 0 through the valve chamber is and thence through the exhaust ports w to the atmosphere.

As will be noted, during the rearward travel of the piston, the valve 9 will have been moved to the rearward end of the chamber so that the relief port o is covered by the head 6 of the valve and the rearward end of the cylinder will be in communication with the atmosphere through the relief port a, the valve chamber is and the exhaust port w. In this way a greater portion of the air compressed by the piston F will be exhausted from the cylinder and only a sufficient amount of compression will remain in the cylinder to cushion the rearward stroke of the piston F.

I claim:

In a fluid actuated rock drill, the combination of a cylinder and piston, a valve chest, inlet passages leading from the ends of the valve chest to the ends of the cylinder, a distributing valve in the valve chest, said valve having a bore throughoutits length through which live pressure fluid passes, a central head on the valve having actuating pressure areas, shoulders on the valve of lesser diametrical dimension than the head forming holding pressure areas, crossed kicker passages leading from the cylinder to the valve chest for conveying pressure fluid under working pressure to the actuating areas for actuating the valve, and live'air leak ports in the valve chest for conveying live pressure fluid from the inlet passages to the holding areas to hold the valve in its limiting positions and for exhausting such pressure fluid through the cylinder from the holding areas before the valve has reached its extreme seating position.

In testimony whereof I have signed this specification. Y

LEWIS o. Barnes. 

